Who is making the most from ripping off Sentai? Saban. Yes, he has writers and things handling the stories, but it's his ballgame. As I said, it's your opinion if you feel that this Power Ranger stuff isn't a rip off.
I feel that if people wanted to see these characters he should have joined hands with the Japanese and brought Sentai to the states in all it's heavenly glory. Not hack it to pieces or use the same stories just changing the characters races. You don't have to feel as I do, but I swear I look at what has been done to Sentai (all for the love of money) to be wrong. Maybe I am a purist (i'm the same way with my comic book movies). I see no need for Power Rangers when Sentai beats their brains in.
The Japanese even used Power Ranger themes better then they did. Look at Go-Buster for example. They took the terms "Megazord" and "It's Morphing Time" and made that crap pop. Even going further by making the smaller monsters be called Metaroids. The Japanese know and love this genre alot. Unlike the Americans who take it as a joke (go on any public forum and mention Power Rangers and watch them cut you to pieces if it's not a site like this).
So I don't care if they are paying for the footage. It isn't their original idea to hack and slash as they have done. If they had made the series better I could understand, but they haven't. I just think I rather give all my support to the original source being that it's handled so much better then how it is in the states.
As the old saying goes, "to each their own".
